Recently, it is common to take into consideration the potential for reduction in the air resistance and lift of a motorcar when modifying the external form thereof. However, a motorcar has never been manufactured in which the visible external form is independent of the external form presented to the wind, or which invisibly incorporates in the visible car body a subsidiary car body with an aerodynamic design which is smaller at its front and rear portions than that of the visible car body. More specifically, there is no prior art which enables the aerodynamic car body to be incorporated in the visible car body. It is also unknown to treat in the aerodynamically most suitable manner a car's wheels and the wheel space which can be the main barrier to achieving reduction in the air resistance of the car.
The present invention resides in transforming the space in which the wheel moves up and down into an air passage through which air can pass smoothly, and aims at the provision of an aerodynamically efficient car body which is able to offer reduced air resistance and lift.